Typically, the monopods come without heads. Depending on how you plan on using the monopod will impact your choice. Example: Do you plan on hiking (moving a lot) ? Do you only use it at sporting events, plays (usually static at same spot)?
If you ever plan on shooting portrait with the pod (and without a bracket), you will need to purchase a head as well to allow you to swivel 90 degrees. Typically, this will add noticeable weight to the pod. I consider my monopod(s) as add-ons to the camera and weight is important to me. I chose a graphite rod. I do own a head for the pod and the weight difference is quite noticeable. When I use my bracket with the pod, I do not use the head (my bracket can do portrait/landscape shots).
My pod also works as a walking stick while doing landscape/animal photography.